Frederick Fennell, the master band conductor who founded the famed Eastman Wind Ensemble and raised band performance to an art form, died early Tuesday at his home in Siesta Key, Fla. He was 90.

Mr. Fennell died in his sleep, his daughter, Cathy Fennell Martensen, said in an e-mail message circulated to friends and colleagues.

Through the pioneering Eastman ensemble, started in 1952, and a slew of recordings in the 1950's and 1960's, Mr. Fennell set a new standard of wind ensemble performance, often assigning just one player to each part and infusing band music with a new level of expressivity.

"He was arguably the most famous band conductor since John Philip Sousa," said Jerry F. Junkin, a professor of music at the University of Texas at Austin and artistic director of the Dallas Wind Symphony, where Mr. Fennell was principal guest conductor.

Before Mr. Fennell, band music was often considered lowbrow entertainment with an assembly-line feel.

"He was the first person to really record so much of the band repertoire," Mr. Junkin said. "He was really the first conductor to do interpretive readings of some of that repertoire, insightful, interpretive, passionate readings."

Mr. Fennell also taught for more than 50 years at the music camp at Interlochen, Mich. He took his meals with the students in the cafeteria and was often seen in a sweater from his colorful collection. Although he was just over five feet tall, his conducting style was equally flamboyant, and his almost shoulder-length white hair attracted attention. He expressed a wish to have his ashes scattered in the woods at Interlochen, his daughter said.

Mr. Fennell studied conducting at Tanglewood with Serge Koussevitzky at the same time as Leonard Bernstein and conducted many full orchestras, including the Cleveland Orchestra and the London and St. Louis symphonies. He also founded the Kosei Wind Orchestra of Tokyo. A concert hall in Kofu, Japan, was named after him, among countless academic and civic honors he received.

His lasting influence on wind ensemble performance included conducting dozens of bands around the country as a guest. He was a luminary in band associations, wrote books and essays on woodwind performance and did many contemporary editions of period band scores. He was also known for making pioneering records for the Telarc label in the early days of digital recording in the 1970's.

Mr. Fennell was born on July 2, 1914, in Cleveland and attended the Eastman School of Music in Rochester, where he studied percussion.

In her e-mail message, Ms. Martensen recounted that on his deathbed Mr. Fennell said, "I cannot die without a drummer." She added that his last words were: "I hear him. I'm O.K. now."